The title compound, C25H26Cl2FN3O4S, contains two bio-active moieties (thio­barbituric acid and fluoro­quinolone). In the crystal, mol­ecules are linked via C—H⋯O and C—H⋯F hydrogen bonds, forming two-dimensional slab-like networks lying parallel to the bc plane. The benzene ring substituted by F and Cl atoms and the 4-chloro­butyl group seem to be partly disordered, however attempts to model the disorder were unsuccessful.

A vast number of fluoroquinolones (Baker et al., 2004) such as ciprofloxacin and moxifloxacin have therapeutic efficacy as anti-infective agents (Li et al., 2000; Mitscher, 2005). The prepared molecule contains two bio-active moieties (thiobarbituric acid and fluoroquinolone), which may have a high impact biological effect.

From the X-ray structural analysis, it is interesting to note that this structure presents some zwitterionic character, since the bond length for C3—C10 is 1.449 (5) Å, intermediate between carbon-carbon single bond and double bond, while bond angles around C10 are close to 120°: C13—C10—C11 = 119.8 (4), C11—C10—C3 = 120.5 (4), and C13—C10—C3 = 119.5 (4)°. The crystal structure reveals the negative charge to be localized at the thiobarbituric-acid ring, with a contribution of the enolate form [C10—C11 = 1.418 (6), C10—C13 = 1.406 (6), C11—O1 = 1.231 (5), C13—O2 = 1.229 (5) Å; see Sweidan et al., 2012]. The carbon-sulfur bond length is 1.665 (5) Å, which is close to that observed in a 2-thioxo-1,2,3,4-tetrahydropyrimidine derivative [1.673 (9) Å, Shishkin et al., 1997; see also Al-Qawasmeh, 2012].

The displacement parameters in the 4-chlorobutyl branch are rather high, indicating, together with residual electron density in the vicinity, some degree of disorder. For example, C22—C23 bond length, 1.402 (9) Å, is a bit short for a single C—C bond. After convergence, it seems that benzene ring substituted by F1 and Cl1 could also be partly disordered. However, attempts to model such disordered parts did not improve the picture.

The title compound was prepared as followed: 8 ml of thionyl chloride was added to a solution containing 1.5 g (5.3 mmol) of 7-chloro-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid in 15 ml of dry THF. The resulting solution was refluxed for 6 h, then cooled, and evaporated under reduced pressure to remove the excess thionyl chloride. To the resulting residue, a solution of 1,3-diethyl-2-thiobarbituric acid (1.19 g, 6.0 mmol) and 1.5 ml (10.0 mmol) of dry triethylamine in 20 ml of dry THF were added, at room temperature. After stirring overnight, the resulting precipitate was filtered off, washed with H2O/THF (1:2), and dried under reduced pressure. Yield: 1.5 g (51%). This solid was recrystallized from dichloromethane/diethylether, affording brownish crystals. A flat elongated crystal was mounted and data collected using five omega scans and a total of 277 frames with an exposure time of 76 s per frame.

Fig. 1. ORTEP drawing showing the molecular conformation of the title compound. Displacement ellipsoids for non-H atoms are drawn at the 30% probability level. Hydrogen atoms are represented as small spheres of arbitrary radii.

4-Chlorobutyl 7-chloro-1-cyclopropyl-4-(1,3-diethyl-4,6-dioxo-2-sulfanylidene-1,3-diazinan-5-ylidene)-6-fluoro-1,4-dihydroquinoline-3-carboxylate top

Acknowledgements

The authors gratefully acknowledge financial support from the Deanship of Scientific Research at the University of Jordan. The X-ray structural work was done at the Hamdi Mango Center for Scientific Research of The University of Jordan, Amman 11942, Jordan.

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.